Invasive Non-Native Species

Our freshwater and marine environments are under threat. Invasive non-native species are one of the top five drivers for biodiversity loss worldwide, and present a huge threat to native species, aquatic environments and our sport.



Plants and animals from other countries are finding their way into our waterways after being imported for ornamental or agricultural use. Many of these non-native species wither and die in the wild. Others survive, but don’t spread rapidly. A few spread like wildfire, as they don’t have the natural controls of diseases, predators and grazers to keep them in check. They can therefore do massive damage to our water environment and negatively impact our fishing. These are known as Invasive Non-Native Species. 

Recognising the detrimental impacts invasive species can have on our environment and economy, an EU Regulation on Invasive Alien Species (1143/2014) came into force in January 2015. The Angling Trust are working to ensure effective implementation of this regulation and to encourage Government to take action on invasive species more broadly. This work has been funded by fishing licence money as part of our National Angling Strategic Services contract with the Environment Agency.

We are also working with organisations like The Rivers Trusts and the Riverfly Partnership’s Angling Monitoring Initiative groups to set up procedures to control and eradicate these species that threaten the objectives of the Water Framework Directive. 

Part of the Regulation also involves the production of guidance for different recreational users – including anglers – that outlines measures clubs, anglers and the land owners can implement to reduce the risk of invasive species being introduced to their waters. This includes a variety of free materials and information on the potential risks of invasive species spread associated with fish stocking and habitat management. For more information, please see below:

Simple measures every angler can undertake to stop the spread of invasive species:

Invasive species can be spread between water bodies a variety of ways. One of these includes anglers accidentally carrying these species on their clothing and fishing gear from one site to another. 

The Angling Trust urges all anglers to carefully think about this and how you can help with what is called biosecurity. 

The Check Clean Dry campaign launched in 2011 provides guidance to anglers and other water users on how to clean equipment to ensure the removal of unwanted organisms and diseases. After fishing ensure to: 


  1. Check your equipment and remove any attached organisms,
  2. Clean your equipment ideally using hot water for at least 15 minutes or a pressure washer,
  3. Dry out your clothing and fishing tackle, especially nets, ideally in sunlight, before fishing again. 

This is especially important when going to fish a different water and returning from a trip abroad – carp anglers know the importance of this in spreading KHV, salmon anglers will know the importance with potentially spreading salmon fluke Gyrodactylus salaris. The deadly crayfish plague carried by signal crayfish can survive on damp clothing for up to 10 days (for more information and posters see the crayfish section). If drying out is not a viable option, consider having one set of kit for your favourite water and another for travelling to waters you fish less often. Disinfecting kit is an option using Virkon aquatic 1% solution generally available through the aquatic trade.  

To order a free Check Clean Dry sign to install at your water please contact [email protected]

Another major route for invasive species to enter the wild is through species escaping from nearby gardens, or unwanted plant material being dumped into our waterways. The Be Plantwise campaign aims to increase awareness amongst gardeners, pond owners and retailers of the impact aquatic plants and provide information on how to dispose of these plants correctly. The Angling Trust assisted in the design of this scheme and supports this best practice outlined in the campaign and encourages anglers to check the names of plant species before introducing any species into their waters. 

Catchment based approach

Anglers are already expending considerable effort in trying to tackle this threat to our fishing, but we recognise that to be more effective this needs to be co-ordinated on a catchment basis. The Angling Trust is therefore working with a variety of stakeholders to achieve this. Our work to eradicate Floating Pennywort on the River Kennet and Colne highlights how angling clubs, consultants and environmental organisations can come together to coordinate action within a catchment. By working together, we can make a significant impact on these threats to our fishing. 


Updates on invasive species work, including the most significant developments being undertaken by different environmental groups, are available on the Non-native Species Secretariat webpage. 

Identification, Reporting and Control

You might have invasive non-native species on waters which you own, lease or fish. With the technical and financial assistance of the Environment Agency and the GB Non Native Species Secretariat we have amalgamated information on invasive species pest identification and control to help our members and others to take effective action. 

A table of 17 invasive species including Killer shrimp, Topmouth gudgeon and Signal crayfish and information on their identification and control is available in the table below. Identification sheets for other high-risk species are available here. 

For some species such as Signal crayfish, there are no known total eradication techniques at present. We are supporting research into control of signal crayfish with a report outlining the results of modified crayfish trapping available here. 

Alongside ID guides there are also an online iRecord form that you can access from your phone to record sightings of invasive non-native species. We would also encourage you to undertake the GBNNSS e-learning training on invasive species including information on identification, control and recording. 


Stop the spread

Invasive plants, animals and diseases harm the environment, impact native fish species reduce the quality of fishing. Please help to stop them by following the Check, Clean, Dry code. 

To promote the Check, Clean, Dry code to other anglers, a series of materials have been produced for the angling community. This includes: 

  1. Check Clean Dry aluminium signs – contact [email protected] if you are interested in having one delivered
  2. Check Clean Dry posters – download a copy here
    1. Coarse angling sign
    2. Welsh language coarse angling sign
    3. Game angling sign
    4. Marine angling sign
    5. Welsh language marine sign
  3. Check Clean Dry leaflets and stickers – find out more here
  4. Fisheries biosecurity plan template – outlining the potential risks of invasive species introduction associated with fish stocking, habitat management, competitions and measures that can be implemented to minimise the risk. Available soon.
  5. Undertake the free e-learning on invasive non-native species and biosecurity.